A method of fitting a semiconductor chip on the surface of an integrated circuit board or on the package bottom is known (cf "Assembly techniques of integrated circuits" by V. A. Dubolazov et al., "Vischa shkola" PH, Kiev, 1987, pp.60-62 (in Russian)), said method comprising a gripping of the chip with a tool which appears as a bar having a porthole for vacuum admission, and a recess in the end face, shaped as a frustum of pyramid, said recess being large enough for the chip to sink half its size into the recess. Then the board and the tool are heated, the chip is transferred to the bonding site and pressed against the mounting surface, whereupon vibration is applied thereto. Once the chip is attached with a binder (solder or adhesive) the source of vacuum is cut off and the tool is withdrawn.
However, the method discussed above fails to provide fitting of chips into the board volume (either into the recess in the board surface or in to the hole therein) so as the surface of the chip is coincided with that of the board. This results in a low reproducibility of the length of leads and reduces the chip bonding accuracy.
One more prior-art fitting method is known (GB, B, 2,138,205), wherein the manufacturing process of a microwave circuit consists in that the semiconductor chip is pressed into the tool which is in fact a bar having a flat end and a capillary in the central portion, said capillary so flaring out towards the end tool portion that the edges of the tool end portion overlap the peripheral chip portion and extend beyond the limits thereof, thus locally deforming the substrate. As a result, a hollow is formed having the shape and depth corresponding to those of the chip which is held in the substrate by virtue of its thrusting against the faces of the hollow. Reduced deformation of the lower substrate surface is attained due to use of the initial recess.
However, with the aforesaid method for chip fitting the substrate is deformed and its flatness is upset. Moreover, the method suffers from low manufacturability.
When pressing the chip into such a substrate it is hard to determine the instant when the pressing is terminated, which might inflict a distortion upon the substrate when the surface of the chip is coinceded with that of the circuit board. The distortion of the substrate reverse side disturbs its flatness, which hampers substrate mounting on a heat sink base.